The clogging of a downspout of an eaves trough with floating debris such as leaves has been a problem for a long time. One solution to this problem has been to prevent the debris from entering the trough by placing a strainer over the entire length of the trough. While effective, this solution requires a great length of strainer material which must be carefully placed and secured over the top edges of the trough.
In order to reduce the amount of strainer material needed, there has been disclosed in the prior art a number of devices which locate a small length of strainer material in the trough above the downspout. These strainers are inclined or sloped in the trough so that the debris backs up on the strainer. Devices such as these are disclosed in the following U.S. Pats.: No. 2,875,712 to Blau, No. 2,669,197 to Van Duzer, No. 571,711 to Twist, and No. 803,316 to Vogel.
Another type of device disclosed in the prior art uses a series of wires acting as a screen instead of a mesh-like strainer. For example, in U.S. Pats. No. 520,993 to Keller and No. 737,138 to Ralson a wire screen is placed over the opening of a downspout in a modified eaves trough. In both of these patents, the screen is inclined slightly downwards so that debris collected on the screen will slide off the end of the screen and fall out of the modified trough. However, for both of these devices, a modified trough must be used. A wire screen for a standard trough is disclosed in U.S. Pat. No. 2,210,248 to Lighthill. In this patent, a stepped screen is placed on a trough so that as debris accumulates, it is moved up from one step to the other by the water level and finally up and over the edge of the trough. Another prior art device having flexible fingers which can conform to the parallel troughs of a corrugated roof is disclosed in U.S. Pat. No. 3,864,267 to Nelems.
There are a number of disadvantages, however, to these prior art devices. The devices using meshed strainer material in a trough are subject to plugging as the debris get stuck in the apertures of the strainer. This plugging is further increased as the water pressure behind the debris builds up. The devices using wire screens also suffer disadvantages. For some of these devices, a modified or custom trough must be used. In addition, most of the devices can not be easily adapted to fit the variety of trough shapes which are in existence. The screen with flexible fingers can be used in a variety of corrugated roof troughs but the flexible fingers would be unsuited for a single large trough as the fingers would be easily forced to flex out of the way of the debris pushed by the water.